[ADVICE NEEDED] How to deal with teenage forgetfulness??

I desperately need advice. Desperately. 

The question is pretty straightforward, but i'll explain my situation further in a bit more detail. I'm growing out of that awkward teenager phase so i'm still SUPER forgetful. I get the thing where you're just sitting there and you randomly forget what you're doing, or who you are or what your name is and whatnot. Then I snap out of it in in like 10 minutes to a week usually and it's fine.

In this instance I'll be talking about I was late to class. I did everything to try to make it to that class at quickly as I could in spite of this. I felt myself forgetting so I wrote down the name of the class, the professor's name and the room number, but when i looked at the paper i just....couldn't read it. It wouldn't comprehend. I was actively writing the info, and looking at it, but I couldn't get up. I couldn't remember the information I was actively looking at. I felt like I was possessed. (not helped at all by my part, if i recall correctly, BEGGING me not to go. Like what the ***?? I dont even know this fool who hasn't helped me with any assignments ever and now he's telling me to tank my grade with an absence?? Ridiculous!!)

And now I'm just wondering. How do you guys manage to remember to do your classes under these conditions? I haven't been able to figure it out, and every time I think about it, another part is just triggered out of no where and I forget again. How in the world are you supposed to remember to go to class when you have all the information written down and you just can't act on it?! how on earth are you guys completing your assignments under these conditions?! TELL ME YOUR SECRETS...please :)